Metal-assisted chemical etch to produce porous group III-V materials

• US 6,762,134 B2
• Filed: 11/20/2001
• Issued: 07/13/2004
• Est. Priority Date: 11/27/2000
• Status: Expired due to Term

• Current Assignee: Board of Trustees of The University of Illinois
• Original Assignee: Board of Trustees of The University of Illinois
• Inventors: Li, Xiuling, Adesida, Ilesanmi, Bohn, Paul W., Sweedler, Jonathan V.
• Primary Examiner(s): Vinh, Lan
• Application Number:
  US09/989,050
• Publication Number:
  US 20020074314A1
• Time in Patent Office: 966 Days
• Field of Search: 438/745, 438/750, 216/56, 216/103, 205/606, 205/665, 205/674
• US Class Current: 438/745
• CPC Class Codes: H01L 21/0332 characterised by their composition, e.g. multilayer masks, materials
• CPC Class Codes: H01L 21/30612 Etching of AIIIBV compounds
• CPC Class Codes: H01L 21/3081 characterised by their composition, e.g. multilayer masks, materials
• CPC Class Codes: H01L 33/18 within the light emitting region
• CPC Class Codes: H01L 33/30 containing only elements of Group III and Group V of the Periodic Table

Abstract

A thin discontinuous layer of metal such as Au, Pt, or Au/Pd is deposited on a Group III-V material surface. The surface is then etched in a solution including HF and an oxidant for a preferably brief period, as little as a couple seconds to one hour. A preferred oxidant is H₂O₂. Morphology and light emitting properties of porous Group III-V material can be selectively controlled as a function of the type of metal deposited, doping type, doping level, metal thickness, whether emission is collected on or off the metal coated areas and/or etch time. Electrical assistance is unnecessary during the chemical etching of the invention, which may be conducted in the presence or absence of illumination.

Claims

1. A method for producing porous Group III-V material, the method comprising steps of:

depositing a thin discontinuous layer of metal on a Group III-V material surface;

forming the porous Group III-V material by etching the Group III-V material surface in a HF and oxidant solution, said etching being conducted without external electrical bias.

2. The method according to claim 1, wherein said step of etching is conducted in the absence of illumination.

3. The method according to claim 1, wherein said step of etching is conducted in the presence of illumination.

4. The method according to claim 1, wherein said metal comprises Pt.

5. The method according to claim 1, wherein said metal comprises Au.

6. The method according to claim 1, wherein said metal comprises Pd.

7. The method according to claim 1, wherein said metal comprises a combination of metals selected from the group consisting of Au, Pt and Pd.

8. The method according to claim 1, wherein said oxidant comprises H₂O₂.

9. The method according to claim 1, wherein the thickness of said metal is less than approximately 10 nm.

10. The method according to claim 1, wherein said etching is conducted for a time period between about 2 seconds and one hour.

11. The method according to claim 1, wherein said Group III-V material comprises GaN.

12. A method for producing porous Group III-V material, the method consisting of the following steps:

depositing a thin discontinuous layer of metal on a Group III-V material surface;

forming the porous Group III-V material by etching the Group III-V material surface in a HF and oxidant solution for a period of about two seconds up to 60 minutes.

13. The method according to claim 12, wherein said step of etching is conducted in the absence of illumination.

14. The method according to claim 12, wherein said step of etching is conducted in the presence of illumination.

15. The method according to claim 12, wherein said metal comprises Pt.

16. The method according to claim 12, wherein said metal comprises Au.

17. The method according to claim 12, wherein said metal comprises Pd.

18. The method according to claim 12, wherein said metal comprises a combination of metals selected from the group consisting of Au, Pt and Pd.

19. The method according to claim 12, wherein said oxidant comprises H₂O₂.

20. The method according to claim 12, wherein the thickness of said metal is less than approximately 10 nm.

21. The method according to claim 12, wherein said etching is conducted for a time period between about 2 seconds and one hour.

22. The method according to claim 12, wherein said Group III-V material comprises GaN.

23. A method for producing porous Group III-V material, the method comprising steps of:

depositing metal on a Group III-V material surface in a thickness sufficient to permit nucleation that forms nanometer size metal particles and small enough to prevent formation of a continuous metal layer;

forming the porous Group III-V material by etching the Group III-V material surface in a HF and oxidant solution for a period of about two seconds up to 60 minutes, said etching being conducted without external electrical bias.